Pelican Technical Article:

BMW E30 and E36 3
Series On Board DiagnosticsJared Fenton

Did you know that your BMW 3 Series has an internal
diagnostic program built into the computer? Not many people know about
this. On the BMW 3 Series, there is a way that you can diagnose common
engine problems without having to purchase a code tool or take it to the
dealer to have it scanned. This is one of those neat little features of
the Service Indicator Computer; the series of lights directly under the
tachometer and speedometer that remind you to change the oil and perform
service. In this tech article, I will provide you with the procedure for
checking the fault codes and what the codes mean. This guide will help you
to diagnose any possible problems with your car.

This article is written for both the BMW E30 and E36 3 Series
cars (up to 95) and should work on both models where a Service Indicator
Computer is used. I will go over the small differences between the early
and late cars, as they differ slightly. Keep in mind that this procedure
will not work on early cars with Motronic 1.1.

Now on the E30 models, get in the car and put the key in the
ignition and turn it to the second turn or “ON” position, but do not
start the car. Now, press the accelerator pedal all the way to the floor,
then let it release all the way back. Now repeat the depress/release cycle
4 more times fairly quickly, but not too fast. It may take some time to
get this timing down correct. It should only take you a few seconds to do
this. What this does is activate the wide-open throttle switch and the
idle switch 5 times. This then sends a signal to the Motronic ECU to send
fault codes to the Service Indicator Light.

On the E36 models, the procedure works the same way, but the
timing at which you press/release the gas pedal is faster than on the E30.
Just keep at it, and you will eventually get the correct speed.

Watch the “Check Engine” light. It should blink once, and
then start blinking a series of four numbers. For instance, say this is a
sequence you see… the light blinks once, then twice, then four times and
lastly four times. If you read it correctly this means that the SI light
is reading out the code 1244 (faulty camshaft sensor) The codes appear as
a series of flashes for each digit. The flashes indicating one digit are
about one second apart, the next digit will appear after a couple seconds
interval. If there are no faults in the car, the computer will flash out
the number 1444.

Here is the list of
codes and what they indicate.

1211DME Control Unit

1215Air Mass Sensor

1216Throttle Potentiometer

1218Output Stage, Group 1

1219Output Stage, Group 2

1221Oxygen Sensor 1

1212Oxygen Sensor 2

1222Lambda Control
1

1213Lambda Control 2

1223Coolant Temperature Sensor

1224Intake Air Temperature Sensor

1225Knock Sensor 1

1226Knock Sensor 2

1227Knock Sensor 3

1228Knock Sensor 4

1231Battery Voltage/DME Main Relay

1232Throttle Idle Switch

1233Throttle Wide Open Throttle Switch

1234Speedometer A Signal

1237A/C Compressor Cut Off

1242A/C Compressor

1243Crankshaft Pulse Sensor

1244Camshaft Sensor

1245Intervention AEGS

1247Ignition Secondary Monitor

1251Fuel Injector 1 (or group 1)

1252Fuel Injector 2 (or group 2)

1253Fuel Injector 3

1254Fuel Injector 4

1255Fuel Injector 5

1256Fuel Injector 6

1257Fuel Injector 7

1258Fuel Injector 8

1261Fuel Pump Relay Control

1262Idle Speed Actuator

1263Purge Valve

1264EGO Heater

1265Fault Lamp (check engine light)

1266VANOS

1267Air Pump Relay Control

1271Ignition Coil 1

1272Ignition Coil 2

1273Ignition Coil 3

1274Ignition Coil 4

1275Ignition Coil 5

1276Ignition Coil 6

1277Ignition Coil 7

1278Ignition Coil 8

1281Control Unit Memory Supply

1282Fault Code Memory

1283Fuel Injector Output Stage

1286Knock Control Test Pulse

1444No Fault Codes

Well, there you have it - it's
really not too difficult at all. If you would like
to see more technical articles like this one, please continue
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Comments and Suggestions:

lola J

Comments: does this release procedure work on 1996 318is, if not..is there a procedure that does work to give me a code?

March 20, 2014

Followup from the Pelican Staff: " This article is written for both the BMW E30 and E36 3 Series cars (up to 95"

You will need a BMW scan tool to read the codes. - Nick at Pelican Parts

Aviator

Comments: I'm the original owner of an '89 M3. The car is totally stock. I have made no modifications. I have bad idle, bad mpg, smelly exhaust. I'm trying to read the codes out using your procedure of 1 slow depress and release of accelerater, followed by 4 more quickly. I can't get any codes to readout. Does your procedure apply to E30 M3's. This may have nothing to do with getting the readout to respond but I have the original sticker on the shock tower in the engine compartment that reads "OBD Exempt" which I understand means On Board Diagnostics Exempt. I need to show this sticker to novice smog testers from time to time.

January 7, 2013

Followup from the Pelican Staff: The procedure may not apply to your M3. Some tools can connect through the BMW diagnostic connector. - Nick at Pelican Parts

hotrodln

Comments: thanks for the free tech article. I was shopping for a code reader when i found it. You will have my continued business! Pat

August 1, 2011

Followup from the Pelican Staff: - Nick at Pelican Parts

Thanks for the feedback, keep checking in for more tech advise.

JPC

Comments: Title should indicate 95 and earlier - shouldn't have to read the article to find out it doesn't apply